The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. The technical field generally relates to positive displacement pumps, and more specifically but not exclusively to high pressure positive displacement pumps. Operations with positive displacement pumps having several cylinders occasionally encounter high pressure situations, failures of one or more pumps within the pumping system, or otherwise perform pumping operations requiring a broad range of fluid rates and pressures within the same pumping operations. Changing a displacement of a pump in the present art includes utilizing a pump with a multi-speed transmission, performing operations on a pump requiring significant disassembly of the pump, and/or exposure of personnel to treating iron or other fluid conduits during high pressure pumping operations. In certain contexts, including oilfield pumping applications, shutting down pumping for extended periods during a pumping operation can be detrimental to the success of the pumping operation. Therefore, further technological developments are desirable in this area.